membrane transport Flashcards
1
Q
simple diffusion
A
- membrane is fully permeable
- only small, non-polar molecules can pass through non-polar hydrocarbon tails
2
Q
facilitated diffusion
A
- diffusion of ions and polar (water-soluble) molecules through cell surface membranes using specific transport proteins
- water molecules (polar but small molecules) enter and exit cell mainly by facilitated diffusion as osmosis is inefficient in terms of squeezing through transient pores
3
Q
active transport
A
- involves special molecules of the membrane called protein pumps and requires ATP
- occurs against concentration gradient
- highly selective (more needed more impt)
- most membrane pumps are specific to particular molecules (selective)
4
Q
bulk transport
A
- occurs by movements of vesicles of matter (solids/liquids) across the cell surface membrane
- ATP is required
5
Q
exocytosis
A
process by which cells export products such as enzymes by means of vesicles
6
Q
endocytosis
A
substances imported into cell
7
Q
phagocytosis
A
wholesale import of solid matter
8
Q
pinocytosis
A
bulk import of fluids
